U.S. patent number 7,244,899 [Application Number 11/348,782] was granted by the patent office on 2007-07-17 for keypad assembly for portable terminal.
This patent grant is currently assigned to Samsung Electronics Co., Ltd.. Invention is credited to Dong-Hoon Jang, Sun-Tae Jung, Mun-Kue Park.
United States Patent |
7,244,899 |
Jung , et al. |
July 17, 2007 |
Keypad assembly for portable terminal
Abstract
A keypad assembly for a portable terminal according to the
present invention includes: a keypad having pad portions with a
plurality of key buttons placed thereon, light guide plates
disposed between the pad portions, and reflection units disposed on
the light guide plates to direct the light toward the key buttons;
light sources for providing the light toward the reflection units;
a plurality of spacers disposed below the light guide plates for
separating the light guide plate from a substrate and for
supporting the light guide plates; switches disposed below the pad
portions under the key buttons for applying signal to the
substrate; and a casing for enclosing the keypad.
Inventors: |
Jung; Sun-Tae (Anyang-si,
KR), Jang; Dong-Hoon (Suwon-si, KR), Park;
Mun-Kue (Suwon-si, KR) |
Assignee: |
Samsung Electronics Co., Ltd.
(Suwon-Si, Gyeonggi-Do, KR)
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Family
ID: |
37036921 |
Appl.
No.: |
11/348,782 |
Filed: |
February 7, 2006 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20060289283 A1 |
Dec 28, 2006 |
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Foreign Application Priority Data
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Jun 28, 2005 [KR] |
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10-2005-0056494 |
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Current U.S.
Class: |
200/314 |
Current CPC
Class: |
G06F
1/1626 (20130101); G06F 1/1662 (20130101); G06F
3/0202 (20130101); H01H 13/83 (20130101); H04M
1/22 (20130101); H04M 1/23 (20130101); H01H
2219/056 (20130101); H01H 2219/06 (20130101); H01H
2219/062 (20130101) |
Current International
Class: |
H01H
9/20 (20060101) |
Field of
Search: |
;200/5A,512,310,314,317,341,406,516 ;341/22 ;345/168-170
;379/368,433.07 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1265261 |
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Dec 2002 |
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EP |
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2159654 |
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Dec 1985 |
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GB |
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WO 02/15211 |
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Feb 2002 |
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WO |
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Primary Examiner: Friedhofer; Michael A.
Attorney, Agent or Firm: Cha & Reiter, L.L.C.
Claims
What is claimed is:
1. A keypad assembly for a portable terminal comprising: a keypad
having a plurality of pad portions with a plurality of key buttons
placed thereon, a light guide plates disposed between the pad
portions, and a reflection units including a triangular shaped
cross-section and being disposed on the light guide plates to
direct light toward the key buttons; a light source configured to
provide the light toward the reflection units; a plurality of
spacers disposed below the light guide plates, the spacers
configured to separate the light guide plate from a substrate and
to support the light guide plates; and a plurality of switches
disposed below the pad portions under the key buttons, the switches
configured to apply signal to the substrate.
2. The keypad assembly for the portable terminal as claimed in
claim 1, wherein the reflection units comprises a reflective
mirror.
3. The keypad assembly for the portable terminal as claimed in
claim 1, wherein the reflection units includes a reflection coating
layer.
4. The keypad assembly for the portable terminal as claimed in
claim 1, wherein the reflection units is disposed on an upper
portion of the light guide plate and wherein position of the light
guide plate is determined according to an arrangement of the key
buttons.
5. The keypad assembly for the portable terminal as claimed in
claim 1, wherein the reflection unit has an isosceles triangular
shaped cross section to direct the light from the light source
toward each of the key buttons in all direction.
6. The keypad assembly for the portable terminal as claimed in
claim 1, wherein the reflection unit has a right triangular shaped
cross section to direct the light from the light source toward the
key buttons.
7. The keypad assembly for the portable terminal as claimed in
claim 1, wherein the light guide plate is made of same material as
that of at least one of the plurality of pad portions to perform a
function of at least one of the plurality of pad portions.
8. The keypad assembly for the portable terminal as claimed in
claim 1, wherein at least one of the plurality of pad portions on
which one of the plurality of key buttons is placed further
includes a protuberance to activate at least one of the plurality
of switches and further includes a reflection pattern to partially
guide the light reflected by means of the reflection unit to the
key buttons.
9. The keypad assembly for the portable terminal as claimed in
claim 1, wherein the light sources are disposed between the
spacers.
10. The keypad assembly for the portable terminal as claimed in
claim 1, wherein thickness or the light guide plate is same as that
of at least one of the plurality of pad portions.
11. The keypad assembly for the portable terminal as claimed in
claim 1, wherein thickness of the light guide plate is larger than
that of at least one of the plurality of pad portions.
12. The keypad assembly for the portable terminal as claimed in
claim 11, wherein the light guide plate further includes a tapered
portion at a region in contact with at least one of the plurality
of pad portions in order to prevent light loss.
13. The keypad assembly for the portable terminal as claimed in
claim 1, further comprising a casing, the casing including a
protuberance integrally formed thereon, so as to bring the
reflection unit into a close contact with the light guide
plate.
14. The keypad assembly for the portable terminal as claimed in
claim 13, wherein the reflection unit is attached to the
casing.
15. The keypad assembly for the portable terminal as claimed in
claim 1, wherein the spacers arc made of same material as that of
the light guide plate and are integrated with the light guide
plate.
16. The keypad assembly for the portable terminal as claimed in
claim 1, wherein the light guide plate is made of silicon
material.
17. The keypad assembly for the portable terminal as claimed in
claim 1, further comprising a casing configured to enclose the
keypad.
18. The keypad assembly for the portable terminal as claimed in
claim 1, wherein the reflection unit has a conical shape.
19. The keypad assembly for the portable terminal as claimed in
claim 1, wherein the reflection unit has a semi-conical shape.
20. The keypad assembly for the portable terminal as claimed in
claim 1, wherein the reflection unit is configured to reflect a
portion of the light input from the light source in a direction
parallel to a surface of the at least one of the plurality of pad
portions on which one of the plurality of key buttons is placed.
Description
CLAIM OF PRIORITY
This application claims priority to an application entitled "Keypad
Assembly for Mobile Phone," filed with the Korean Intellectual
Property Office on Jun. 28, 2005 and assigned Serial No.
2005-56494, the contents of which are incorporated herein by
reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a portable terminal such as
cellular phones, Personal Digital Assistants (PDA), Personal
Communication System (PCS), game phones, camera phones, Digital
Multimedia Broadcasting (DMB) phones, and more particularly to a
portable terminal having a lighting function to enable a user to
dial another user at night.
2. Description of the Related Art
In general, "a portable terminal" implies an electronic device that
a user can carry for communication with another user wirelessly. In
consideration of portability, the design of such a portable
terminal focuses not only toward a compactness, slimness, and
lightness, but also toward providing multimedia capabilities to
allow the user to enjoy a wider variety of functions. Thus, future
portable terminals will be used in a multimedia environment to
provide the Internet access and its related functions globally.
Currently, a conventional portable communication terminal allows a
voice communication as well as a high-speed data communication.
Further, as consumer's demands have increased, various services
have been provided using a wireless communication technology for
transmitting and receiving data at a high speed. Most portable
terminals are now equipped with an embedded or an external camera
lens to transmit image signals and the like.
The portable terminal typically includes data input and output
units, data transmitting and receiving units, an antenna unit and
the like. The data input unit includes a keypad assembly or a touch
screen to input data. The keypad assembly is constructed with key
buttons, silicon rubber, dome switches and the like. A well-known
liquid crystal display unit is generally used as data output
unit.
Moreover, the portable terminal has a lighting device for lighting
the keypad and may include a plurality of light emitting diodes
arranged on a printed substrate, or an inorganic electro
luminescent body inserted in an elastic pad disposed on the printed
substrate. FIG. 1 shows such a conventional keypad assembly 100,
which includes a switch substrate 120, a plurality of light
emitting diode 122, and a keypad 110.
The keypad 110 is made from an elastic material, i.e., silicon and
other material made from the combination of silicone and a poly
urethane film. The keypad 110 includes a plate-shaped elastic layer
111, a plurality of key buttons 112 having characters printed
thereon and mounted on the elastic layer 111, and a plurality of
protuberances 111a formed at a lower surface of the key pad 110.
The key buttons 112 and the protuberances 111a are vertically
aligned to each other.
The switch substrate 120 includes a plate-shaped printed substrate
120a and a plurality of switches 121 facing the protuberance 111a
of the keypad 110. Each of the switches 121 is provided with a
conductive contact and a metal dome entirely covering the
conductive contact. The light emitting diodes 122 are disposed at
predetermined positions on the printed substrate 120a.
However, in order to guarantee the operation of the switch 121, the
light emitting diodes 122 are disposed on the printed substrate
120a, each of which is not vertically aligned to the corresponding
key button 112. That is, the light emitting diodes 122 are disposed
between the switches 121. As a result, the light emitted toward the
respective key button 112 from the light emitting diode 122
diverges in all directions, so that the illumination of the key
buttons 112 becomes non-uniform and dark. That is, as the light
emitted from the light emitting diode is shed through the side of
each key button, the number or characters printed on the respective
key button cannot be displayed with a uniform brightness.
Therefore, in order to overcome the above-mentioned problems, it is
necessary to use a larger number of light emitting diodes for
lighting the key buttons, which increases the cost for assembling
the light emitting diodes as well as electric power consumption of
the light emitting diodes, thereby causing the manufacture of the
keypad assembly to be economically inefficient.
SUMMARY OF THE INVENTION
Accordingly, the present invention has been made to solve the
above-mentioned problems occurring in the prior art and provides
additional advantages, by providing a keypad assembly for a
portable terminal, which can be illuminated with a uniform
brightness for the entire keypad.
One aspect of the present invention is to provide a keypad assembly
for a portable terminal, which has a local light source for key
buttons disposed at the edge of the keypad, thereby providing a
uniform surface light source for the entire keypad.
Another aspect of the present invention is to provide a keypad
assembly for a portable terminal, which has a light source
consuming minimum electric power.
Still another aspect of the present invention is to provide a
keypad assembly for a portable terminal, which has a top view-type
light source instead of the side view-type light source, so that it
can provide a uniform brightness.
In one embodiment, there is provided a keypad assembly for a
portable terminal includes: a keypad including pad portions having
key buttons placed thereon, light guide plates disposed between the
pad portions, and reflection units disposed on the light guide
plates to direct the light toward the key buttons; light sources
for providing the light toward the reflection units; a plurality of
spacers disposed below the light guide plates for separating the
light guide plate from a substrate and supporting the light guide
plates; switches disposed below the pad portions under the key
buttons for applying signal to the substrate; and a casing for
enclosing the keypad.
BRIEF DESCRIPTION OF THE DRAWINGS
The above features and advantages of the present invention will be
more apparent from the following detailed description taken in
conjunction with the accompanying drawings, in which:
FIG. 1 is a sectional view of a conventional keypad assembly of a
portable terminal;
FIG. 2 is a perspective of a portable terminal having a keypad
assembly according to an embodiment of the present invention;
FIG. 3 is a sectional view of a keypad assembly for a portable
terminal according to an embodiment of the present invention;
FIG. 4 is a sectional view of a keypad assembly for a portable
terminal according to an embodiment of the present invention, in
which a pad portion has the same thickness as that of a light guide
plate;
FIG. 5 is a sectional view of a keypad assembly for a portable
terminal according to an embodiment of the present invention, in
which the light guide plate has a tapered portion;
FIG. 6 is a sectional view of a reflection unit in a keypad
assembly for a portable terminal according to another embodiment of
the present invention;
FIG. 7 is a sectional view of a keypad assembly for a portable
terminal according to another embodiment of the present invention,
in which a pad portion has the same thickness as that of a light
guide plate; and
FIG. 8 is a sectional view of a keypad assembly, which is enclosed
by a casing, according to the embodiment of the present
invention.
DETAILED DESCRIPTION
Hereinafter, embodiments of the present invention will be described
with reference to the accompanying drawings. For the purposes of
clarity and simplicity, a detailed description of known functions
and configurations incorporated herein is omitted to avoid making
the subject matter of the present invention unclear.
FIG. 2 shows a portable terminal 300 having a keypad assembly
according to the present invention. The portable terminal 300
includes a speaker 310, a display unit 320, a keypad assembly
having a plurality of key buttons 330, and a microphone 340, which
are arranged on an upper surface of the portable terminal 300. The
key buttons 330 are protruding out of a casing 301 so that the top
of each key button 330 is exposed. Therefore, a user can touch and
push the top of the key button 330 to input data or activate the
phone.
Referring to FIG. 3, the structure of a keypad assembly 200
according to the present invention will be described. As shown in
FIG. 3, the keypad assembly 200 according to the present invention
includes a keypad, a light source 230, spacers 225, switch portions
240, and a casing 250 (see FIG. 8).
More specifically, the keypad includes pad portions 210 provided
with a plurality of key buttons K, a light guide plate 220 disposed
between and in parallel with the pad portions 210, and a reflection
unit 260 which directs light transmitted from the light source 230
toward each key button K. The pad portions 210 are made from
materials having a high elasticity. The light guide plate 220 is
preferably made of materials having a good transmittance in the
visible ray region. The light guide plate 220 is made of the same
material as that of the pad portion 210, and preferably is made of
elastic silicon materials so that the light guide plate 220 can
play the role as a part of the pad portion 210.
The reflection units 260 are disposed on an upper surface of the
light guide plate 220, specifically, on portions corresponding to
the key buttons arranged on the substrate. The positions of the
reflection units 260 are determined based on the relative positions
of the arranged key buttons K. This configuration causes the
reflection units 260 to reflect the light to the pad portion 210 so
as to give an entirely uniform brightness to the keypad. That is,
the positions of the reflection units 260 are determined depending
on the arrangement of the key buttons K deployed in the portable
terminal. However, it is possible to locate the reflection units
260 at other positions that are not dependent on the arrangement of
the key buttons K. For example, it is possible to locate the
reflection units 260 at positions at which the reflection units 260
can direct a sufficient light toward the key buttons at the edge
portions, which are relatively dark.
The respective reflection unit 260 may include a reflection mirror
or a unit having a reflective coating layer with a high
reflectance. The unit having the reflective coating layer may
include a metallic material and a reflective coating layer coated
on the metallic material. It is unnecessary to limit the reflection
unit 260 to the reflective coating layer made of the metallic
material, thus the reflection unit 260 may be made by preparing an
inclined structure on the light guide plate and then coating a
suitable material on the incline structure. The suitable materials
include materials having a higher refractive index than the light
guide plate. Each of the reflection units 260 has a triangular
shape in section, which includes at least one inclined surface.
That is, FIG 3 shows a cross section of the reflection units 260,
but the reflection unit 260 is a conical shape. Accordingly, a
light emitted from the light source 230 is transmitted by the
conical reflection units in all directions. The reflection unit 260
has a reflective coating layer formed on the inclined surface
facing the light source 230.
The light source 230 is disposed vertically below the reflection
unit 260 and between the spacers 225 or between the key buttons K
to emit the light toward the reflection unit 260 so as to give an
entirely uniform brightness to the keypad. Of course, the light
source 230 is locally disposed in a dark region of the keypad. It
is preferred that a light emitting diode is used as the light
source 230 in consideration of the lifetime and the environment.
The dome switches 240 are metal dome switches, which apply electric
signals to a processor as the user presses a key.
The pad portion 210 having the key buttons K further includes
protuberances 212 to activate the dome switches 240. Each of the
protuberances 212 includes a reflection pattern 214 to locally
guide the light reflected by the reflection unit 260 toward each of
the key buttons K. The region of the reflection pattern corresponds
to the width of the respective key button K in order to transmit
the reflected light to the key button K as much as possible.
The spacers 225 is disposed below the light guide plate 220 in
order to support the light guide plate 220 spaced apart from the
substrate B. The spacers 225 are made of the same material as that
of the light guide plate 220. More specially, it is economical to
integrate the spacers 225 with the light guide plate 220 using
silicon material. However, some structure does not include the
spacer 225 and can be separated from the guide plate 220. The
spacers 225 supporting the light guide plate 220 may be used to
adjust the height of the light guide plate 220 with respect to the
pad portions 210. Thus, the size of the spacers may be changed
according to its purpose. Further, the spacers 225 may be disposed
near the dome switches 240, for example, below the pad portion 210
as well as the light guide plate 220.
The reflection unit 260 as shown in FIGS. 3 to 5 has an isosceles
triangular shape in a cross section, particularly a conical shape,
which is comprised of a reflective mirror that a reflective layer
is disposed on its surface. The FIGS. 3 to 5 show a cross section
of the reflection unit with the first and second inclined surfaces
261 and 262.
The first and second inclined surfaces 261 and 262 are symmetric to
each other and serve to direct the light from the light source 230
toward the key button K. However, it should be noted that the shape
of the reflection unit 260 may have different shapes other than the
triangular shape, specifically a conical shape. The reflection unit
260 may be formed in convex or concave shape having a certain
curvature. Here, it is important that the reflection unit 260 must
have a surface shape capable of preventing the light from the light
source 230 from leaking out of the keypad and transmitting the
light to the key button K as much as possible.
The light guide plate 220-1 shown in FIG. 4 has the same thickness
as the pad portion 210 in the portion in contact with the pad
portion 210.
Meanwhile, it should be noted that the light guide plate does not
have to have the same thickness as the pad portion. Preferably, the
light guide plate 220 is thicker than the pad portion 210 in order
to prevent the light guided from the light source through the light
guide plate 220 from leaking and transmit it to the pad portion 210
as much as possible.
FIG. 5 shows a light guide plate 220-2 having a tapered portion
224. In the case in which the light from the light source 230 is
directed toward the pad portion 210 by way of the reflection unit
260, it is possible to transmit a large quantity of light when the
light guide plate 220 is thicker than the pad portion 210 as
described above. However, in this case, a discontinuity occurs at
the connecting point between the pad portion 210 and the light
guide plate 220, so it is necessary to prevent the loss of the
light in advance. For this reason, the tapered portion 224 is
provided to the light guide plate 220-2. That is, the tapered
portion 224 can prevent the loss of the light in the discontinuity
region due to a difference in the thickness between the light guide
plate 220 and the pad portion 210.
Preferably, the above-mentioned light guide plate 220 may be formed
integrally with the pad portion 210 and may be made of materials
having low hardness, high elastic coefficient, high elastic
recovery force, and high permeability, for example, silicon
material or polyurethane material in order to play a role as the
pad portion 210.
In the keypad assembly having a plurality of key buttons K employed
in the portable terminal, as shown in FIG. 6, the key buttons K-1
placed at the outer edge of the keypad may possibly darker during
operation due to distance. Thus, it is desirable for the reflection
unit 260-1 to reflect the light in only one direction for such key
buttons. To address this problem, the reflection unit 260-1 having
a right triangular shape in a cross section, specifically a
semi-conical shape, with a single inclined surface 263 may be
provided according to anther embodiment of the present invention.
The FIG. 6 shows a cross section of the reflection unit having the
right triangular shape. The single inclined surface 263 directs the
light from the light source 230 toward the key buttons K-1. It
should be noted that other functions, such as pad portion,
switches, light guide plate, and light source, shown in FIG. 6 is
omitted to avoid redundancy as they are already described with
reference to FIG. 3.
The reflection unit 260-1 is disposed on the light guide plate
220-2, and more specifically is aligned vertically above the light
source 230. Although FIG. 6 shows the light guide plate 220 and the
pad portion 210 having different thicknesses from each other, it is
possible that the light guide plate has the same thickness as the
pad portion at the portion at which the light guide plate is in
contact with the pad portion. FIG. 7 shows the light guide plate
220 and the pad portion 210 having the same thickness. In the case
in which the light guide plate has a different thickness from the
pad portion, the tapered portion as shown in FIG. 5 can be adopted
for the light guide plate to minimize the light loss.
Referring to FIG. 8, a casing 250 encloses and separates the keypad
assembly from its outer environment. The casing 250 includes a
protuberance 252 normally extending downward from an inner surface
of the casing 250. The casing 250 may be integrally formed with the
protuberance 252 by injection molding while the reflection unit 260
is attached to the protuberance 252 of the casing 250. Otherwise,
the protuberance 252 and the reflection unit 260 may be
independently made and then assembled in an assembling process.
Referring back to FIGS. 3 8, an operation of the lighting unit
provided to the keypad assembly according to the teachings of the
present invention will be described hereinafter.
As shown in FIGS. 4 8, the light from the light source 230 is
mostly transmitted in a vertical direction of the light guide plate
220-2, while hardly transmitted in a horizontal direction of the
light guide plate 220-2. Then, the light transmitted from the light
source 230 is directed by means of the reflection unit 260 to the
light guide plate 220-2, which in turn horizontally transmits the
light toward the key buttons K. The light introduced to the light
guide plate 220-2 in this way is subjected to a total reflection at
the boundary between the light guide plate 220-2 and the reflection
unit 260, so tat almost all of the light is transmitted through the
light guide plate 220-2. When the light reflected by the reflection
unit 260 reaches the reflection pattern 214, the transmission angle
of the light exceeds the critical angle, so the light is refracted
upward and emitted out of the pad portion 210. Here, the reflection
patterns 214 arc coarsely formed at a site adjacent to the light
source 230, while closely formed at a site far from the light
source 230. Thereby, it is possible to ensure the entirely uniform
brightness to the keypad.
As described above, the present invention can provide a keypad for
a portable terminal with a uniform illumination. In addition, the
present invention is provided with the reflection pattern to
locally emit light to the key button. The light guide plate has the
same thickness as the pad portion in the connecting region of the
pad portion and the light guide plate, so as to minimize the light
loss. As a result, the present invention allows the keypad assembly
to have a small number of light emitting diodes (LEDs), resulting
in a decrease in the numbers of the LED and in the reduction of
manufacturing cost. Furthermore, the present invention can be
applied to the region of the key buttons which are arranged at a
side or at the edge of the pad portion having a relative darker
area during operation, so as to provide a uniform illumination
through out the key button regions mainly.
While the invention has been shown and described with reference to
certain preferred embodiments thereof, it will be understood by
those skilled in the art that various changes in form and details
may be made therein without departing from the spirit and scope of
the invention as defined by the appended claims.
* * * * *